Electronic balancing system for balancing road vehicle wheels

Abstract

An electronic balancing system for balancing road vehicle wheels, of the type for balancing mounted wheels, includes a processor driving a light beam projector for projecting directly on the wheel the position where a counterweight is to be attached to eliminate a condition of unbalance the value whereof is indicated on a seven-segment display.

I claim: 
     
       1. Electronic balancing system for balancing mounted road vehicle wheels, comprising: a wheel to be balanced having marks on it;   electromechanical transducer means to supply electric signals proportional to the vibration induced by the unbalance of the wheel;   a pair of optoelectronic transducer means to supply electric signals when energized by said marks;   analog and digital processing means including programmer means; a programmable gain amplifier electrically connected to said electromechanical transducer means and programmer means for supplying a current proportional to the number set in the programmer means; a variable gain amplifier connected to said programmable gain amplifier and said period meter means; active band-pass filter means connected to said variable gain amplifier and said period means synchronized with the rotation speed of the wheel; analog to digital converter means including storage means and comparator means connected to said filter means to indicate the peak value of the electrical signal produced by said electromechanical transducer means; squarer means connected to said band-pass filter means to convert said electrical signal into an indentical phase square wave; and display means connected to said analog to digital converter means to indicate the value of the unbalancing weight;   a digital processor including period meter means connected to said squarer means and to said optoelectronic transducer means to locate the position of said unbalance;   light beam projector means connected to said digital processor to project onto the wheel a beam of light indicating the position of unbalance.   
     
     
       2. Electronic balancing system according to claim 1, wherein said digital processor comprises: flip-flop means connected to said optoelectronic transducer means for detecting and storing the direction of rotation of the wheel;   a microprocessor unit including reference clock means;   a data bus connected to said flip-flop means, said transducers and said microprocessor unit;   a read-only store operatively connected to said microprocessor unit controlling the transfer of data thereto;   a read-write store interfacing with said microprocessor unit, receiving partial processing data therefrom;   an arithmetic unit interfacing with said microprocessor unit.   
     
     
       3. Electronic balancing system according to claim 1, wherein said digital processor comprises: flip-flop means connected to said optoelectronic transducer means for detecting and storing the direction of rotation of the wheel;   sequence signal generating means connected to one of said pair of optoelectronic transducer means;   a sixteen-bit presettable up-down counter means operatively connected to said sequence signal generating means, functioning as period meter and counting down from a stored digit or number;   a store connected with said counter means and said sequence signal generating means for storing the rotation period of the wheel;   position counter means connected to said sixteen-bit counter means and including storage means connected to said squarer means and said flip-flop means.   
     
     
       4. Electronic balancing system according to claim 1, wherein said projector means project on the wheel a luminous cross useful as reference in centering said balancing system with respect to the hub of said wheel. 
     
     
       5. Electronic balancing system according to claim 1, wherein said projector means include a glass support comprising a plurality of opaque sectors and one clear sector, and an optical projection system. 
     
     
       6. Electronic balancing system according to claim 1, wherein said projector means include a stepped motor and a disk allowing a light beam therethrough in a predeterminate position thereof. 
     
     
       7. Electronic balancing system according to claim 1, further comprising display means for visually indicating the position of a counterweight to be attached to the wheel, wherein a series of numbers is projected onto the wheel.